There is no universal definition of public diplomacy (PD); nations and individuals define it to suit their varying interests. The State Department, for one, currently notes that the mission of PD is:

to support the achievement of U.S. foreign policy goals and objectives, advance national interests, and enhance national security by informing and influencing foreign publics and by expanding and strengthening the relationship between the people and Government of the United States and citizens of the rest of the world.

In the late 1990s, and especially in our new century, this American-developed term, public diplomacy, morphed into a global verbal phenomenon, not only among governmental but also non-government entities. Today PD can be read/heard the world over in English or in translation (China, Japan, South Korea, India, Turkey, Israel, Ghana, South Africa, Canada come to mind). Indeed, while compiling my near-daily Public Diplomacy Press and Blog Review, I often find more direct references to public diplomacy in foreign rather than American media (that is, with the term actually cited).

Sir Harold Nicolson (1886-1968), the distinguished Old World diplomat, contends in his classic work, Diplomacy(first edition, 1939), that trying to influence/manipulate public opinion is not diplomacy, but propaganda, an activity he condemns. He writes (p. 92):

A new and serious problem of modern diplomacy is the problem of propaganda. In the days of the old diplomacy it would have been regarded as an act of unthinkable vulgarity to appeal to the common people upon any issue of international policy. It was Canning, in 1826, who first recognized the efficacy of what he called "the fatal artillery of popular excitation."

In an epilogue to his book (1961), Nicolson notes that (pp. 144-145):

In the old days when foreign affairs was recognized to be a specialized study and when their conduct was left to experts, the element of propaganda scarcely entered into consideration. To-day it is sometimes preponderant, being all too apt to backfire or recoil.

Despite these reservations about public diplomacy, its quite revolutionary impact, by iconoclastically modifying a traditional, widely-used noun/activity, has opened the door to much wider interpretations of diplomacy -- and of the kind of people, including non-professional diplomats, who could/should carry it out. PD advocates, if not practitioners, would doubtless agree with a broader dictionary definition of diplomacy than the ones cited above: "tact, skill, or cunning in dealing with people" (some PD-ers, however, would perhaps prefer that "cunning" be left out of the equation).

Granted, in the past diplomacy did not always stand grammatically alone. Gunboat diplomacy was once in quite wide circulation; open diplomacy is referred to by the Office of the Historian at the State Department in its examination of Foggy Bottom's activities; and how can we fail to remember shuttle diplomacy, a term associated with Secretary of State (1973-1977) Henry Kissinger's efforts to bring peace to the Middle East, in part by grabbing the attention of the press (and, indirectly, the public).

A special place in the increased "adjectivizaction" of diplomacy (pardon the jaw-breaking term, but it does describe what's going on) can be traced in part to the British scholar Mark Leonard, who in his 2002 book, Public Diplomacy, introduced the following terms: Co-operative Diplomacy; Competitive Diplomacy; NGO Diplomacy; Diaspora Diplomacy; Political Party Diplomacy; Brand Diplomacy; Business Diplomacy; and Niche Diplomacy (the words are capitalized in the study's table of contents).

In recent decades there has been a veritable global explosion of adjectives applied to diplomacy. Among the terms created by such a linguistic union, many of them considered a subset or variation of public diplomacy, are: people-to-people diplomacy (first labeled in 1956, during the Eisenhower administration, as People-to-People Program); citizen diplomacy (don't let just the dips do it!); science diplomacy (à la mode among results-oriented think-tank professionals); health diplomacy (one down-to-earth way to save humankind); sports diplomacy (enjoy the game!); guerilla diplomacy (coined by a Canadian diplomat critical of his country's staid diplomacy); celebrity diplomacy (let's face it: the stars outshine yawn-producing foreign affairs bureaucrats in engaging ordinary audiences); fashion diplomacy (how to dress properly for diplomatic/popular success).

There is, in our social media age, a verbal collage that is gaining much traction: internet diplomacy. Most would agree that it includes digital diplomacy, the subject of a multitude of press reports pertaining to the cyberspace information war with ISIS. Digital diplomacy (I'm surprised I haven't seen it as a acronym) is also the focus of academic conceptual speculations on its implications/role. For a relatively recent report on DD, see.

Gastrodiplomacy (no, it's not a quick-fix pill for acute indigestion after an official banquet) is a relatively new expression evoking one of humankind's greatest achievements, gastronomy, meant to be shared at the table. But, unlike many other PD related terms, it's a one-word concept. Culinary diplomacy, on the other hand, adheres to the well-established adjective-noun relationship.

I recently was made aware, by a learned linguist, of horticultural diplomacy. A Google search suggests (but of course does not confirm), that it surfaced in 2014. The term (its adjectival component is often used to make a risqué pun) is mentioned in an announcement stating that Stephen Crisp, Head Gardener at Winfield House, the official residence of the United States Ambassador to the United Kingdom, would "talk about managing London's second largest private garden after Buckingham Palace."

I should mention the humorous remark of a distinguished professor of Slavic literature: "Following Foucault, I'm proposing a new concept of 'biodiplomacy' that would apply to all kind of human exchanges (hostages, spies, academics, etc.)." Intrigued by the professor's light but thought-provoking observation, I stumbled upon other versions of biodiplomacy on Google, e.g., "BioDiplomacy uses diplomatic skills to promote global diversity, especially in island communities."

During the George W. Bush administration, Dr. Condoleezza Rice, while Secretary of State (2005-2009), sought to highlight her plans for transformational diplomacy. Whether the Secretary's modification of a time-tested noun was influenced by the growing practice of placing adjectives before diplomacy, I do not know; but she was certainly following a trend, highlighted by her desire of not leaving diplomacy grammatically alone -- and of turning diplomats into social/economic activists rather than simply negotiators or observers crafting reporting telegrams to Washington.

And of course we have the widely-cited and memorable panda diplomacy, which in a way extends diplomacy to animals. Wikipedia:

Panda diplomacy is China's use of giant pandas as diplomatic gifts to other countries. The practice existed as far back as the Tang Dynasty, when Empress Wu Zetian (625-705) sent a pair of pandas to the Japanese emperor.

For countries where pandas are not a native species, dogs could possibly perform "dog diplomacy," a term I have not yet seen. A U.S. pet club in the 1950s claimed, however, that "dogs make the best ambassadors" because they "are capable of hurdling the barriers of language and ideologies in the quest for peace." Writer Lisa Loeb shares this pro-canine attitude in her Ambassador Dogs, in which she writes that dogs are "ambassadors to the world and our own local communities. They come to serve and love us as only they know how."

My own minor, rather frivolous, contribution to the creation of the new diplomatic jargon -- pubic diplomacy -- did not appeal to the wordmasters of the universe. But it does occasionally appears as a typo in some U.S. Embassy internal memoranda; need I note that the American ambassador's office would not automatically be amused if it received a message from the "Pubic Diplomacy Section."

On a more serious note, President Woodrow Wilson, dedicated to making the world safe for democracy and hostile to the secret schemings of Great War Eurodiplomats, was enamored with the word public, as can be seen in the first of his Fourteen Points (1918):

The programme of the world's peace, therefore, is our programme; and that programme, the only possible programme, as we see it, is this:

I. Open covenants of peace, openly arrived at, after which there shall be no private international understandings of any kind but diplomacy shall proceed always frankly and in the public view.

Below are recent media entries with adjectival modifications (vulgarisations?) of diplomacy -- which, perhaps, have contributed to a refinement (dilution?) of the meaning of this unexciting but venerable word. Should one be optimistic/pessimistic about such a development? Let the reader decide.